A Rh(Ii)/Phosphoric Acid Co-Catalyzed Three-Component Reaction Of Diazo-Ketones With Alcohols And Azonaphthalenes: Access To Indole Derivatives Via A Formal [3+2]-Cycloaddition

A novel dearomatization/rearomatization/cyclization oxonium ylide trapping process is well developed via a dirhodium(ii) acetate and phosphoric acid cooperatively catalyzed multi-component reaction of diazo-ketones with alcohols and azonaphthalenes. This protocol provides an efficient route to synthesize N-substituted 1-amino-indole derivatives in good yield under mild reaction conditions.